Metastatic tumors to the pancreas: Balancing clinical impression with cytology findings

Abstract

Backgrounds/Aims Metastatic lesions of the pancreas (PMET) account for 1%–5% of all malignant solid pancreatic lesions (SPL). In this study we evaluated the utility of endoscopic ultrasonography with fine needle aspiration (EUS-FNA) in diagnosing PMET. Methods Patients who underwent EUS-FNA at a community referral center between 2011–2017 for SPL were identified. Clinical, radiologic, and EUS-FNA features of those with PMET were compared to those with primary solid tumors of the pancreas: pancreatic adenocarcinoma (PDAC) and neuroendocrine tumors (PNET). Results A total of 191 patients were diagnosed with solid pancreatic malignancy using EUS-FNA: 156 PDAC, 27 PNET, and eight (4.2%) had PMET. Patients with PMET were less likely to have abdominal pain (25.0% vs. 76.3% vs. 48.2%; p < 0.01) or obstructive jaundice (37.5% vs. 58.3% vs. 0%; p < 0.01) compared to PDAC and PNET. Those with PMET were more likely to have mass lesions with/without biliary or pancreatic ductal dilatations (100% vs. 86.5% vs. 85.2%; p < 0.01) and lower CA19-9 (82.5 ± 43.21 U/mL vs. 4,639.30 ± 11,489.68 U/mL vs. 10.50 ± 10.89 U/mL; p < 0.01) compared to PDAC and PNET. Endosonographic features were similar among all groups. Seven (87.5%) patients with PMET had a personal history of malignancy prior to PMET diagnosis. The primary malignancy was renal cell carcinoma in five PMET. Conclusions PMET are exceedingly rare, comprising less than 5% of SLP. Patients with PMET are less likely to present with symptoms and mostly identified by surveillance imaging for the primary malignancy.

Comments on and Illustrations of the EFSUMB CEUS Guidelines: Transabdominal and Endoscopic Ultrasound Features of Intrapancreatic Metastases and the Role of Multiparametric Imaging and EUS-Guided Sampling in Rare Pancreatic Tumors

“…In the largest series of EUS-guided sampling of solid pancreatic lesions (n = 1108, among them 672 neoplastic lesions), Krishna et al diagnosed 53 pancreatic metastases (4.8% of all solid FPL and 7.9% of all neoplastic FPL) [19,20]. Three smaller studies diagnosed intrapancreatic metastases using EUS-guided sampling in 4.2-4.7% of all neoplastic solid FPL [21][22][23].…”

“…In the case of an imaging diagnosis of a pancreatic tumor, the most important differential diagnosis in patients with previous extra pancreatic tumors is whether the tumor is a pancreatic metastasis or a primary pancreatic tumor (PDAC or PanNENs). Interestingly, the diagnosis of pancreatic metastases with EUS-guided sampling was the first manifestation of a malignant disease in 12.5% [21], 16% [29], 18.8% [30], and 50% of cases [31] in different studies. Lung carcinomas and gastric carcinomas were the most common primary tumors of intrapancreatic metastases in autopsy studies [27,32] (Table 2).…”

“…When comparing intrapancreatic metastases with PDAC and PanNENs, cytology from EUS-guided sampling was less sensitive in metastases [21]. Therefore, other authors advocated for the use of histological material [62,64,97] by EUS-guided sampling.…”